Roof drill bit and associated coupler

ABSTRACT

A coupler for use with a roof drill bit includes an elongate coupler body having a forward end for removably attaching the roof drill bit thereto and a rearward drive end. The elongate coupler body contains an interior bore therein and a dust port formed on an outer surface of the elongate coupler body, wherein the dust port is in communication with the interior bore.

BACKGROUND OF THE INVENTION

The invention relates to a roof drill bit that has a typical use of drilling boreholes in mine roofs. More particularly, the invention pertains to a roof drill bit with associated coupler.

Expansion of an underground mine such as, for example, a coal mine, requires digging a tunnel. Initially this tunnel has an unsupported roof. In order to support and stabilize the roof in an established area in an underground tunnel, bore holes are drilled in the roof. The apparatus used to drill these holes typically includes a drill with a long shaft, i.e., drill steel, attached to a drill bit wherein a roof drill bit is detachably mounted to the drill steel at the distal end thereof. To commence the drilling operation, the roof drill bit is then pressed against the roof and the drilling apparatus is operated so as to drill a bore hole in the roof. The bore holes may extend between two feet to greater than twenty feet into the roof. These bore holes are filled with resin and roof bolts are affixed within the bore holes. A roof support, such as roof panels, is then attached to the roof bolts.

As one can appreciate, the drilling operation generates drilling debris. It is important to remove or evacuate this drilling debris from the vicinity of the borehole. More particularly, it is important to remove the drilling debris from the vicinity of where the roof drill bit initially engages the earth strata so as to decrease wear on the roof drill bit and increase the overall efficiency of the drilling operation. Examples of such roof drilling arrangements are shown in U.S. Pat. No. 8,807,248 to Bise et al. and U.S. Pat. No. 8,002,054 to Swope et al. (both of which are assigned to Kennametal Inc. of Latrobe, Penn., who is also the assignee of the present application). In both of these examples, evacuation ports are formed in the roof drill bit body which is integrally formed with the roof bit cutting end thus requiring replacement of the whole assembly due to wear during use.

Thus, it would be highly desirable to provide an improved roof drill bit arrangement that overcomes limitations, disadvantages and/or shortcomings of known such arrangements.

SUMMARY OF THE INVENTION

In accordance with an aspect of the invention, a coupler for use with a roof drill bit includes an elongate coupler body having a forward end for removably attaching the roof drill bit thereto and a rearward drive end. The elongate coupler body contains an interior bore therein and a dust port formed on an outer surface of the elongate coupler body, wherein the dust port is in communication with the interior bore.

In accordance with another aspect of the invention, an apparatus includes a roof drill bit for drilling a bore hole in a mine roof, the roof drill bit having a cutting end and an opposing attachment end. The apparatus further includes a coupler having a forward end for cooperating with the attachment end of the roof drill bit and a rearward drive end, the coupler containing an interior bore therein and a dust port formed on an outer surface of the coupler, wherein the dust port is in communication with the interior bore.

In accordance with an additional aspect of the invention, a roof drill bit assembly for use in drilling a bore hole in a mine roof includes a roof drill bit having a cutting insert and a roof bit base, wherein the cutting insert is affixed to the roof bit base. The assembly also includes a coupler having a forward end for cooperating with the roof bit base of the roof drill bit and a rearward end, the coupler containing means for removing debris while drilling the bore hole.

These and other aspects of the present invention will be more fully understood following a review of this specification and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1C are exploded views of a roof drill bit assembly, in accordance with an aspect of the invention.

FIG. 2 is an assembled isometric view of a portion of the roof drill bit assembly of FIGS. 1A-1C, in accordance with an aspect of the invention.

FIGS. 3A-3B are assembled views of the roof drill bit assembly of FIGS. 1A-1C, in accordance with an aspect of the invention.

FIGS. 4A-4B are exploded and assembled views, respectively, of an additional roof drill bit assembly, in accordance with an aspect of the invention.

FIG. 5 is an exploded view of an additional roof drill bit assembly, in accordance with an aspect of the invention.

DETAILED DESCRIPTION

Referring to FIGS. 1-3B, there is shown a roof drill bit assembly generally designated as 10, in accordance with an aspect of the invention. In one aspect, the assembly 10 includes a roof drill bit 12 suitable, for example, in drilling a bore hole in a mine roof. In one particular aspect, the roof drill bit 12 can include a cutting insert 14 and a roof bit base 16. The cutting insert 14 forms a cutting end and the roof bit base 16 forms an opposing attachment end, as will be described herein. The cutting insert 14 can be received in a slot 18 formed in the roof bit base 16 and is affixed thereto. Brazing is a typical method useful to attach or affix the cutting insert 14 to the roof bit base 16 within the slot 18. However, it will be appreciated that other roof drill bit arrangements may be used in accordance with aspects of the invention.

In one aspect, the hard insert 14 typically comprises a hard material such as, for example, cemented (cobalt) tungsten carbide. Conventional cemented (cobalt) tungsten carbide materials useful for a hard cutting insert 14 include, for example, a composition of cobalt-tungsten carbide wherein the cobalt ranges between about 2 weight percent and about 12 weight percent with the balance tungsten carbide and recognized impurities. More specifically, a preferred composition for the cutting insert 14 comprises about 6 weight percent cobalt and the balance tungsten carbide and recognized impurities. There should be an appreciation that there is no intention to limit the scope of the invention by the recitation of specific cemented carbide compositions or ranges for the cemented carbide compositions.

In another aspect, the assembly 10 includes a coupler 20 configured for cooperating with and removably attaching the roof drill bit 12 thereto. More specifically, the coupler 20 has an elongate coupler body 22 (typically formed of steel or a like material) having a first end or a forward end 24 for cooperating with and removably attaching the roof drill bit 12 thereto. The coupler body 22 also has a second end or a rearward drive end 26 for attaching to, for example, a drill steel (not shown) and/or a drive tool such as a drill (not shown).

A drilling operation generates drilling debris and it is important to remove or evacuate this drilling debris from the vicinity of the borehole. More particularly, it is important to remove the drilling debris from the vicinity of where the roof drill bit 12 initially engages the earth strata so as to decrease wear on the roof drill bit 12 and increase the overall efficiency of the drilling operation. Thus, the coupler 20 includes formed in the coupler body 22 an interior bore 28 and at least one dust port 30 (also generally referred to as a vacuum port) formed on an outer surface 32 of the elongate coupler body 22, wherein the dust port 30 is in communication with the interior bore 28 to allow dust/debris to enter into the dust port 30 and flow through the bore 28 away from the drilling area. In one aspect, the dust port 30 is positioned adjacent the forward end 24 of the coupler body 22 so as to be proximate to the roof drill bit 12 and the drilling area. In the illustrated embodiment, the coupler 20 includes two, symmetrically opposing dust ports 30.

During a drilling operation, the roof drill bit 12 experiences the most wear and needs to be periodically replaced. Therefore, aspects of the invention provide for the roof drill bit 12 to be removably attached to the coupler 20 so that the roof drill bit 12 can be replaced as needed. In contrast to a roof drill bit being integrally formed with a body that includes dust ports and a bore, it will be appreciated that by removably attaching the roof drill bit 12 to the coupler 20, the coupler 20 with dust ports 30 does not need to be replaced along with the roof drill bit 12 thus reducing use of materials.

In order to removably attach the roof drill bit 12 to the coupler 20, the invention provides means for removably attaching the roof drill bit 12 to the coupler 20. Still referring to FIGS. 1-3B, there is illustrated a spring clip arrangement 32 for removably attaching the roof drill bit 12 to the coupler 20, in accordance with one aspect of the invention. Specifically, the spring clip 32 includes a biasing member 34 for insertion into an attachment opening 36 formed in the forward end 24 of the coupler 20. The biasing member 34 is flexible and resilient thus allowing for a button member 38 of the spring clip 32 to be inserted into and extend through an aperture 40 formed in the forward end 24 of the coupler 20 (see, for example, FIG. 2).

In order to then removably attach the roof drill bit 12 to the coupler 20, the button member 38 can be pressed inward to allow for the roof drill bit 12 and, in particular the roof bit base 16 to be positioned on the coupler 20 such that an aperture 42 formed in the roof bit base 16 is aligned with aperture 40 in the coupler 20. This allows for the button member 38 to then expand outwardly through the aperture 42 and thus securing the roof drill bit 12 to the coupler (see, for example, FIGS. 3A and 3B) while still providing for it to be easily removed from the coupler 20 by depressing the button member 38 inwardly and removing the roof drill bit 12 as needed for replacement or otherwise.

Referring to FIGS. 4A-4B, there is illustrated an additional arrangement for removably attaching a roof drill bit 112 to a coupler 120 of assembly 110. Specifically, a roof bit base 116 includes a downwardly depending post 144 that extends through an attachment opening 136 formed in the forward end 124 of the coupler 120. The post 144 extends into an upper wall portion 145 of dust port 130. The post 144 includes an aperture 146 (see FIG. 4A) for receiving a pin 148 (see FIG. 4B) that removably attaches the roof bit base 116 to the coupler 120. The pin 148 cooperates with the upper wall portion 145 to hold the roof drill bit 112 in place.

Referring to FIG. 5, there is illustrated an additional arrangement for removably attaching a roof drill bit 212 to a coupler 220 of assembly 210. Specifically, a roof bit base 116 includes a threaded end 249 that is threaded onto threads 250 formed on the forward end 224 of the coupler 220.

It will be appreciated that other arrangements may be provided for removably attaching a roof drill bit to a coupler, in accordance with aspects of the invention.

Whereas particular embodiments of this invention have been described above for purposes of illustration, it will be evident to those skilled in the art that numerous variations of the details of the present invention may be made without departing from the invention as defined in the appended claims. 

What is claimed is:
 1. A coupler for use with a roof drill bit, comprising: an elongate coupler body having a forward end for removably attaching the roof drill bit thereto and a rearward drive end, the elongate coupler body containing an interior bore therein and a dust port formed on an outer surface of the elongate coupler body, wherein the dust port is in communication with the interior bore.
 2. The coupler of claim 1, wherein the elongate coupler body includes an attachment opening formed in the forward end for cooperating with at least a portion of the roof drill bit.
 3. The coupler of claim 1, wherein the elongate coupler body includes an additional dust port symmetrically opposed to the dust port.
 4. An apparatus, comprising: a roof drill bit for drilling a bore hole in a mine roof, the roof drill bit having a cutting end and an opposing attachment end; and a coupler having a forward end for cooperating with the attachment end of the roof drill bit and a rearward drive end, the coupler containing an interior bore therein and a dust port formed on an outer surface of the coupler, wherein the dust port is in communication with the interior bore.
 5. The apparatus of claim 4, wherein the roof drill bit is removably attached to the coupler.
 6. The apparatus of claim 4, wherein the coupler includes an additional dust port symmetrically opposed to the dust port.
 7. The apparatus of claim 4, wherein the coupler includes an attachment opening formed in the forward end thereof for cooperating with at least a portion of the roof drill bit.
 8. The apparatus of claim 4, further including means for removably attaching the roof drill bit to the coupler.
 9. The apparatus of claim 4, wherein the roof drill bit includes a cutting insert at the cutting end thereof.
 10. The apparatus of claim 9, wherein the roof drill bit further includes a roof bit base at the attachment end thereof, wherein the cutting insert is affixed to the roof bit base.
 11. The apparatus of claim 10, wherein the roof bit base is removably attached to the forward end of the coupler.
 12. The apparatus of claim 11, further including means for removably attaching the roof bit base to the forward end of the coupler.
 13. The apparatus of claim 4, wherein the dust port is adjacent the forward end of the coupler.
 14. The apparatus of claim 4, wherein the dust port is proximate to the roof drill bit.
 15. The apparatus of claim 4, wherein the roof drill bit is replaceable.
 16. A roof drill bit assembly for use in drilling a bore hole in a mine roof, comprising: a roof drill bit having a cutting insert and a roof bit base, wherein the cutting insert is affixed to the roof bit base; and a coupler having a forward end for cooperating with the roof bit base of the roof drill bit and a rearward end, the coupler containing means for removing debris while drilling the bore hole.
 17. The roof drill bit assembly of claim 16, wherein the roof drill bit is removably attached to the coupler.
 18. The roof drill bit assembly of claim 17, wherein the means for removing debris includes at least one vacuum port formed on an outer surface of the coupler, the at least one vacuum port in communication with an interior bore formed in the coupler.
 19. The roof drill bit assembly of claim 18, wherein the vacuum port is adjacent the forward end of the coupler.
 20. The roof drill bit assembly of claim 16, further including means for removably attaching the roof bit base to the forward end of the coupler 